After some time, it has been observed men and women who have trouble digesting lactose, disaccharide consisting of glucose and galactose. This situation can cause mild digestive problems, but also stronger problems. It has been attempted to solve this problem in several ways.
Furthermore, it is a high percentage tendency of the population, as can be seen in soft drinks by reducing carbohydrate intake in general and sugars in particular.
An alternative is to provide the person who has lactose intolerance a non-bender lactose enzyme, externally and by oral ingestion prior to the consumption of any dairy product. This solution is cumbersome and requires some planning and discipline by consumer. These features are not in target audience of a product to be marketed massively.
Other option is to apply lactase enzyme into milk fluid as a process for obtaining a product for direct consumption or for preparation of various milk derivatives to ensure low-lactose content.
These processes using lactase into the product provides a sweetness increased by the amount of galactose obtained, resulting an undesirable product by consumer.
U.S. Pat. No. 5,334,399 refers a solution to solve the problem adding potassium chloride to the product where enzymatic hydrolysis was performed. It is a practical solution, but often not allowed for breach of official standards in some countries.
Moreover, said procedure does not allow the assessment of an unwanted component which remains in said product and a process to remove said component to contain more advantages.
Some of said processes use equipment with membranes (filters) of different size (pore size) for different filtration processes such as ultrafiltration. Depending on the pore size, filter becomes more selective as follows:
1. Microfiltration. Used to retain particles according to their size such as bacteria and spores. Let through proteins, fat, sugars, amino acids, minerals and water.
2. Ultrafiltration. Used to retain particles according to their size such as proteins and fat. Let through sugars, amino acids, minerals and water.
3. Nanofiltration. Used to retain particles according to their size such as sacarose or granulated sugar. Let through minerals and water.
4. Reverse osmosis. Let through water and simple minerals.
Thus, it is not possible to determine a milk treatment process for lactose-free milk with similar organoleptic properties such as ultrapasteurized milk without lactose-free process.
A process known currently comprising the steps of:
Equipment use membranes capable to perform microfiltration, ultrafiltration, nanofiltration and reverse osmosis processes to separate milk components.
The process for producing lactose-free or low-lactose milk is as follows:                Subjecting skim or low-fat milk through ultrafiltration process to obtain a retentate and permeate.        UF permeate is then subjected to nanofiltration process to obtain equally said retentate and permeate.        A mixed UF retentate and NF permeate is performed.        
UF and NF processes can perform a partial or even near elimination of lactose content where also part of minerals are lost. This mixture then is subjected to an enzymatic hydrolysis process using β-galactosidase enzyme to reduce lactose content generating glucose and galactose.
Also can perform reconstitution of milk using UF retentate adding water to protein desired level or including reverse osmosis process to concentrate minerals of NF permeate and used for milk reconstitution.
This process provides milk with strange organoleptic characteristics for a normal milk without considering this situation, besides de possibility of using operations which increase the production process.
Any invention that refers the necessary steps (micro, ultra or nano filtration and reverse osmosis) to achieve a lactose-free process for a delactosed or lactose-free milk with a sensory profile equivalent to a pasteurized milk (lactose milk), a partial removal of lactose by physical means and then removing the remaining lactose using lactase enzyme (β-galactosidase enzyme) and obtaining a fully lactose as byproduct, it contributes a non-existent technical knowledge to the state of the art for its protection by a patent.
Patent No. CA2701066, Vernazza, Francesco, refers to a method to obtain low-fat milk comprising at least two steps: first step milk is subjected to an ultrafiltration process to produce an ultrafiltration permeate and retentate after said process and; a second step wherein said ultrafiltration permeate is subjected to a nanofiltration process to produce a nanofiltration permeate and a nanofiltration concentrate after said process. Nanofiltration permeate is continuously recycled directly to the nanofiltration operation to dilute retentate from ultrafiltration and to obtain low-fat milk therefrom. This method does not consider physicochemical conditions to achieve milk with specific organoleptic characteristics.
Mexican patent No. PA/a/2004/011243, Janne Sahlstein, refers to a procedure for producing lactose-free milk products. Process of said invention is characterized by subjecting whole milk to ultrafiltration (UF), nanofiltration (NF) and reverse osmosis concentration, followed by the addition of salt to the UF retentate. Disadvantages of said method is the addition of salt to ultrafiltration retentate adding concentration by reverse osmosis becoming said method more expensive.
Mexican patent No. PA/a/2005/002049 refers to a method for separating milk components, comprising the steps of: passing milk in one-direction-flow through a filtration apparatus; a first step of milk filtration by ultrafiltration means for producing a first liquid filtered and a first concentrated, wherein lactose content of first filtered does not exceed 5.5% by weight; a second step of milk filtration by nanofiltration of first liquid filtered by nanofiltration means for producing a second liquid filtered and a second concentrated, wherein lactose content of second filtered does not exceed 0.15% by weight; a third step of milk filtration by reverse osmosis of second liquid filtered for producing a third liquid filtered and a third concentrated, wherein lactose content of third concentrated does not exceed 0.06% by weight; and wherein first filtered, second filtered and third filtered are removed from filtration apparatus through a first output, a second output and a third output respectively. Said patent contains reverse osmosis.
U.S. Pat. No. 8,445,052, Holst et. al., refers to a process for producing lactose-free or substantially lactose-free milk, preferably without adding water, and the resultant product. Said process comprising the steps of: a) ultrafiltration of original milk for obtaining a first permeate and a first retentate; b) nanofiltration of said first permeate for obtaining a second permeate and a second retentate; mixing first retentate with second permeate for obtaining a mixture; and d) hydrolyze remaining lactose in said mixture for obtaining a hydrolyzed milk. Process provides a lactose-free product with original milk flavor. Said process does not consider the composition of fats, proteins and carbohydrates of original milk.
Processes present in state of the art have the following disadvantages: only used UF retentate and mixing directly retentate with soft water to achieve desired fat and protein levels, making these levels higher to obtain products with good sensory profile.
Also is a complicated and higher cost of operation process due to the application of 3 filtration steps: UF, NF and reverse osmosis.
Also adding flavor to achieve a product that according to Mexican standards, said product not categorized as milk but as flavored milk.
Also incorporate the use of more proteins, up from 3.5% being unaffordable for Mexican market.
Also are methods or processes with lower yields due to the water removal in product and does not return said water in filtration process.
Also said methods or processes use external salts for recovering of lost minerals which increases cost of product.
Also not considered recovery of mineral salts and possible aromatic compound total or partially responsible of milk flavor.